Editing Ulcerative colitis (section)

===Primary sclerosing cholangitis===
Ulcerative colitis (UC) has a significant association with [[primary sclerosing cholangitis]] (PSC), a progressive inflammatory disorder of small and large [[bile duct]]s. Up to 70-90% of people with primary sclerosing cholangitis have ulcerative colitis.<ref name=Langholz /> As many as 5% of people with UC may progress to develop primary sclerosing cholangitis.<ref name=Feuerstein_UC/><ref>{{cite journal | vauthors = Olsson R, Danielsson A, Järnerot G, Lindström E, Lööf L, Rolny P, Rydén BO, Tysk C, Wallerstedt S | title = Prevalence of primary sclerosing cholangitis in patients with ulcerative colitis | journal = Gastroenterology | volume = 100 | issue = 5 Pt 1 | pages = 1319–1323 | date = May 1991 | pmid = 2013375 | doi = 10.1016/0016-5085(91)90784-I }}</ref> PSC is more common in men, and often begins between 30 and 40 years of age.<ref name=Feuerstein_UC/> It can present asymptomatically or exhibit symptoms of itchiness (pruritis) and fatigue. Other symptoms include systemic signs such as fever and night sweats. Such symptoms are often associated with a bacterial episodic version of PSC. Upon physical exam, one may discern enlarged liver contours (hepatomegaly) or enlarged spleen (splenomegaly) as well as areas of excoriation. Yellow coloring of the skin, or jaundice, may also be present due to excess of bile byproduct buildup (bilirubin) from the biliary tract.

In diagnosis, lab results often reveal a pattern indicative of biliary disease (cholestatic pattern). This is often displayed by markedly elevated alkaline phosphatase levels and milder or no elevation in liver enzyme levels. Results of [[endoscopic retrograde cholangiopancreatography|endoscopic retrograde cholangiography]] (ERC) may show bile ducts with thicker walls, areas of dilation or narrowing.  However, some patients with UC and PSC have inflammation that has significantly affected only ramified [[intrahepatic bile ducts]] of smaller diameter, also known as "small ducts", which are not visualized by ERC.<ref name=rasmussen1997>{{cite journal |last1=Rasmussen |first1=H. H. |last2=Fallingborg |first2=J. F. |last3=Mortensen |first3=P. B. |last4=Vyberg |first4=M. |last5=Tage-Jensen |first5=U. |last6=Rasmussen |first6=S. N. |date=June 1997 |title=Hepatobiliary dysfunction and primary sclerosing cholangitis in patients with Crohn's disease |url=https://pubmed.ncbi.nlm.nih.gov/9200295/ |journal=Scandinavian Journal of Gastroenterology |volume=32 |issue=6 |pages=604–610 |doi=10.3109/00365529709025107 |issn=0036-5521 |pmid=9200295}}</ref>{{rp|604, 609}}

In some cases, primary sclerosing cholangitis occurs several years before the bowel symptoms of ulcerative colitis develop.<ref name="Langholz" /> PSC does not parallel the onset, extent, duration, or activity of the colonic inflammation in ulcerative colitis.<ref name="Langholz" /> In addition, colectomy does not have an impact on the course of primary sclerosing cholangitis in individuals with UC.<ref name="Langholz" /> PSC is associated with an increased risk of colorectal cancer and [[cholangiocarcinoma]] (bile duct cancer).<ref name="Langholz" /><ref name="Feuerstein_UC" /> PSC is a progressive condition, and may result in cirrhosis of the liver.<ref name="Feuerstein_UC" /> No specific therapy has been proven to affect the long-term course of PSC.<ref name="Feuerstein_UC" />